Railway signaling system



Sept. 14, 1926. 1,599,470

A. E. Huw

RAILWAY SIGNALING SYSTEM Filed Nov. 6. 1924 2 Sheets-Sheet 1 Hal.

G LT

Sept. 14 1926.

A. E. HUDD RAILWAY SIGNALI NG SYSTEM Filed NOV. 6, 1924 2 Sheets-Sme?I 2Patented Sept. 14, 1926.

UNITED STATES PATENT OFFICE.

ALFRED ERNEST HUDD, OF NEW BRIGHTON, ENGLAND, ASSIGNOR TO AUTOMATICTELEPHONE MANUFACTURING COMPANY, LIMITED, OF LIVERPOOL, ENGLAND.

RAILWAY SIGNALING SYSTEM.

Application tiled November 6, 1924, Serial No.

The present invention relates to improvements in or relating toalternating current track circuits and more particularly coucerns theprovision of special relay arrangements in place ot the usual type ofalternating current relays which require a large operating current. andcan only be operated over comparatively small lengths of track.

It has previously been proposed to use .in alternating current trackcircuits vibratory or alternating current to which a relay` responds toetl'ect a rectiication so that a direct current relay can be operatedthereby. In such arrangements dilticulties arise .in connection with themeans for responding to the frequency ot alternating current supply. Ithas been usual to provide a tuned reed for this purpose in order toensure that the relay will not respond to alternating currents otfrequencies different -troni that ot', the signaling',r current.

An important feature of the present iavention is that the vibrating reedot the responding relay is not tuned, being in iti-.ict substantiallyaperiodic. Partly in order to render the direct current neutral relayimmune to currents of diil'erent frequency and partly to enablealterations in the phase ot the current lowing over the track to bedetermi ned, the vibrating relay which responds to the alternatingcurrent on the track is arranged to rectify alternating currentsuppliedindependently of the track but from the saine source as the currentwhich feeds the track. As satisfactory rectilication is dependent uponthe vibratory member mov` ing in correct phase with the alternatingcurrent to be supplied, a 'further important feature is the provision ofphase adjusting means. One torni of phase adjustment is to insertacondenser or an inductance in series with the responding relay or inseries with the feed circuitl or both, a condenser having the additionaladvantage ot protecting the alternating current apparatus, namely, thefeed transformer secondary or the responding relay from an accidentalconnection beingr established between the live rail and the track rails.The responding relay is preferably otl the type described in Britishspeciication No. 156,353 and such a relay has the additional advantageover relays with tuned reeds that the phase may be adjusted veryaccurately and very readily. In this construction. the polarizing fluxis provided by 748,138, and in Great Britain January 19, 1924.

a U-shaped permanent magnet, each limb of which carries two pole piecesand corre spending coils. The armature is pivoted substantially at itscentre otgravity, so at to be practically aperiodic and as may ha seenfrom the tigures, in either of its operated positions it extendsdiagonally between pole pieces ot opposite polarity. Moreover the magnetand operating coils are pivoted about the same axis as the armature andadjustment is then readily ett'ected by rotating the coils slightly withrespect to the armature, for instance, by means ot a threaded screwoperating against the action of a restoring spring. Phase variations inalternating current track circuits have always been a considerablesource of trouble and have necessitated somewhat expensive mechanism onaccount ot the itact that heavy currents have been used which give riset0 much larger variations of phase than the small currents required bythe invention and further that the line phase adjustment could not beatlected at the receiving end, lith the present invention the linemanhas only to place a voltineter across the terminals of the neutral relayand adjust. the responding relay nntil the 'voltage recorded is amaximum.

In addition to the provision of an aperiodic vibrating relay and specialphase adj usting means a further important feat-ure of the presentinvention in which it ditl'ers 'from prior arrangements is theemployment ot a polarized relay instead of a neutral relay. Thepolarized relay is adapted to give dit ferent indications depending uponwhether the alternating current through the track is in phase with thelocal alternating current or is 1800 out ot phase, and this is otconsiderable value for point detection, three position signaling andother cases where a selective indication is required.

The accompanying dra-wings show by Way of example several embodiments ofthe invention, though naturally additional modifications will readilyoccur to those versed in the art.

Fig. l shows an arrangement of a double rail track circuit fornon-electrilied lines with a standard .neutral direct current relay astrack relay.

Figure 2 indicates a. similar arrangement, in which, however, only onerail is insulated, so that the protective arrangements are different.

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Figure 3 shows i tiouhie rail tr:l circuit with iiniiethinee honds toruse with ete-Striiiii lines. this ineiuding :i inoihtieii errunge- :isection section being' isohiteti troni t tions bj.' the insulators 3 irepresent. a terr-uiting` eur-re zirrying u pre lure i` r in" und tronitl 'ist current is 'l f Condenser 'T to the tred( rai the other enzi oiS Comprising u rre i which us above inentione iy be of vthe tj' xationlo. 15 this reiey energized n current po snpiiiifi h f; denser T to thetruck rrxii' arnizziare 2 :it "quenrs' piu' t'requeney. izzeh tinie:i1-inzitx Contact, u circuit if eonipieteri i'roln ,uur and (3 r the l0Shiloh in i euse is s ioi'n neutrrii relay. tion oi' armature i) is{piene}v the current or relay l Aroni ieuds und 1 l oeires puises o'j:ferr-ent nim the sa i. direction, It is therefore e111, e i undoperates its r1 'niet n'es il und 1Q so :is to close the usuuicontrolling Circuits for ing sli'steni. 'She non-inductie 13 eonneeti smay io und particularly p :redini-'1 Et Wiil be upA tionship of the ableiinportun und ineens is therefore desi current shuii ouh; he ie rentrelay during` e Cave Shown general on L tine adjustment eteteo niechanithe rectifier S.

1lWhen zi treiiA 2 of the seetioi rectifier S is sh eonies on to theriiiis l r under eonsiderzitron 7 orteii outv in 'the usuari r ner, sothat nrrnziture Q cornes to 111 rehiy 1U is reierrsed. @The eoufien'feiiso serres lto he i" L the e -rrent maken nunnsi zint "when whichfunction Cou :'ipt to become unrelizihie.

'esenti case this eiinrriy c t hap 'i certainty oi operation i indeiiet, ent of exteriui phys! :il eonditions. More over. n'hiie, Luned reedswill not no1-inn` i f vii L to currents o1 other iirequef ure :rpt to hethrown into ifofeei'i tions bj; such currents it .iargfe the orr undzigziin, ,3* sensitireners 111115' he Hnpziireifi.

the pre ont invention. tir'L 1ieourse resrionti eluuiiy Weil to "s ett1. pieney Giiiferent from i it :is the Vireiiiiqr ii 1 unrii" eirenniironi ene i 'v'iii a-:feidentzii phrase eorre ts inertia und h f theei'eet or e-istzinee 12j.

nent for eiewtri-I ruil trash' rail l is continuous win t by insulators:auch :is 1;' 1 o. yIhe fe" is non' from power moins if iroughtrzins'i'n'iner ifi, the seeoiuhiir en# cuit including condenser Thereetiiier 22 is in this crise connected throi rondenser and theiinpethui 're 2v2 -which serre to protest the reeitier in eus-e ofContact hetn'ee 1 the traction iii'e *nii anni the iii nsefl itorsiicfzrtniiigpurposes. n

to protect the trui iihir Contingency while Piso rent iin i ini;l undphase znilius" rfhe teer-ring current for the is :liso in this n fornier2S, tri-e zrrung nient oi t 1e vih Contact und the non-inihidtn heini);:is before. Arn'uitu j) und 23() oi the truei( rein); will ngiin controleireiiits :is required in th s nie n miner is with ordinary trickCireuiting. The ir iingeinent shown in Fig. 2 it xiii he noted proviiiedcomp ete isolation Yfrom the direc-'t` current traction Circuits.

ln 3 shon'n i inorifiied arrange nient employing double reetiiiezitionut the reeeii'infcY end, th errang; ments beingr otherrfise siniihi toFigs. l o1 The truck rails :ire represented hy Si und 32 und i323 is thereetitier eontroiringl :i xf'ihrzitinr Contact 3G. l'n this instance,however. armature 3G nmhes Contact in euch oi'r its extreme positionsand the treek relay comprises two "eli lines -`,riti

coils 37 and 38, shunted respectively by noninductive resistances 39 and40. Current is supplied at 34 to the primary of the trans former 35 andthe secondary is connected to the vibrating contact 36 and to thejunction of windings 37 and 38. Hence when the rectifier receivescurrent over the track (supplied as before from the same source as 34)pulses of current are fed alternately to coils 37 and 38. Clearly apulse is now obtained for each half of the wave and additional securityis obtained against the tendeli-y ot the track relay to release betweenthe pulses.

In Fig. 4 is shown an arrangement for electrified lines with a doublerail track circuit so that impedance bands 43 and 44 are necessary toisolate the sections for signaling purposes while giving anuninterrupted return for the traction current. Current is supplied frommains 45 to the transformer 46, from the secondary of which it is fed tothe rails 41 and 42 by way of the condenser 47. The arrangements at thereceiving end include the use of a threeposition track relay, this relaytaking up in addition to its neutral position a different operatedposi,- tion according as the controlling currents are in phase or 18()oout of phase. The rectifier 4S is similar to that shown in Figs. 1, 2and 3 and controls a vibrating contact 49.y The three-position relay ispreferably constructed with a closed annular core 53 on the two halvesof which are located the coils 51 and 52, wound so as to give consequentpoles at the junctions. The ring and coils are assumed to be located ina vertical plane. Pivoted axially at the centre of the coil on a pivot55 is a permanent magnet 54, preferably ot cobalt steel, arranged tooccupy a vertical position when no current is fed to the relay. Thismagnet controls armature 56 so as to close eithercontact 57er 58 whenthe magnet swings to one side or the` other. Current is supplied fromthe power mains 45 through the transformer 50 in the same manner as inFigs. 2 and 3, and the relay is again shunted by anon-inductiveresistance 59.

In operation, current is transmitted over the track in the usual mannerand operates the armature 49 of the rectifier 48 at the supplyfrequency. Each time armature 49 engages its left hand contact a circuitis completed from the secondary of the transformer 50 for the coils 51and 52 in series. Consequent poles are therefore produced, for instanceas shown, and the magnet 54 is rotated in a clockwise direction so as tocause armature 56 to engage with contact 57.

If however a reversing switch is provided in the leads supplying thetransformer 46 or the transformer 50, for instance as shown at and thisswitch is operated, the phase y relationship of the two currentscontrolling the relay is altered by 180. Consequently the pulses ofcurrent fed to the coils 51 and 52 are now in the o posite direction, sothat poles are developedq in the core 53 opposite to those shown andmagnet 54 thus swings in the other direction to close the contact 58.

Thus by means of this arrangement it is possible to use a polarizedrelay and hence obtain three operated positions while retaining thespecial advantages incidental to the use of alternating current in thisconnection.

Vhat I claim is 1. A railway signaling system comprising in combinationan insulated section ot' track, a source of alternating currentconnected to one end of said track, a polarized relay connected to theother end oi" said track, a subw stantially aperiodic vibrating contactinember cont-rolled by said relay, a direct current relay, means forrendering said direct current relay sluggish and nicnas for connectingsaidsource oil alternating current, said vibrating contact member andsaid direct current relay in series so that when said contact membervibrates at the frequency of said alternating current source,uni-directioiial pulses of current are fed to said direct current relay.

2. v A railway signaling system comprising in combination an insulatedsection of track, a source of alternating current connected to one endof said track, a condenser. in circuit with said alternating currentsource for determining the phase thereof. a polarized relay connected tothe other end of said track, a vibrating contact member controlled bysaid relay, a direct current relay, means for rendering said relaysluggish and means for connecting said source of alternating current,said vibrating contact member, and said direct current relay in seriesso that when said Contact member vibrates at the frequency of saidsource and has the correct phase relation` unidirectional pulses otfcurrent are `lied/to said direct current relay.

3.'A railway 'signaling system comprising in combination an insulatedsection of track, a source of alternating current connected to one endot' said track, a polarized relay connected to the other end of saidtrack, a vibrating contact member controlled by said polarized relay, asecond polarized relay, means for rendering said second rela sluggishand means for connecting sai( source of alternating current, saidvibrating Contact member and said second polarized relay in series, sorthat when said contact member vibrates at the frequency of saidalternatingcurrent souice uni-directional pulses of current are ted .tosaid second polarized relay which is theren by operated in one directionor the other i Clie Yiliraiioiis of Said Confed;

one end oi, said traen', a polarized relayv Connected io *elle odrer endof Said track, a 'vibral'iug Contact meiixlier Controlled by said polaized relay, a Seeend polarized relay, lieans for rendering` Said directACurrent relax' Slriggislr and Connecting irre` is independeiit or saidlraek for eo eeting rid source ofi aliernatipg Current. said eoiiaetmember and said second polarized relayv in series, so that when SaidContact member vibrates at fue rrr" ieacy of said source,mii-directional pulse or errrreni are :fed *so il second po larizedrelay v," lr opera ed in one dreriion or lie otlie according afs the'ilirz tionS olf Said eoalgar-l meiiilwr are in pliaSe or i500 out ofphase with Said roaring current souree.

S. A railway Signaling ern Comprising iii eorrilillaiioir iiiinsulare-'d Section or' iravlz. a Source or alreriia'iug currentconnected lo one end of said track, a polarized rela)v Qonieeied to theoiflier end of said haelt, a

ati-rg contact rneriilier coi'rrr'olled la' Said arized relay, a secondpolarized rela)v f mg aa armllar core, @aerei/ing t; ou said eore.arranged afs l'o proreoiizfequent p "i ai opposite elidS of a arreter. a`Jrimineni magnet pvoted on eore, con 'i Closed by Said iperated roeirlier oi? its er:-

j current source. gluig siem eorripr.

allieriialing eurreat i in alare :5oz atri f trad-L a i alghe; allen ilo i ireiii polroiiis, a re lauree eerneeied across polarized relaxl ilSource of all Current7 Said vii r meiriber and salie Second polarizedgela"y ries.

il. fr railmij; signaling ,sj-,Frein eoiiiiirisingg in eo1nl1iiu-i' airiosalaiied seeioii or" tra-eli, Haring errrreiit eoiiueeied lo Olie endof Said ti reir', a polariz d rela)1 eoiiheeled te die oller end olf#aid raelc` :i blurring Contact laeiiilier C'iiirolled by Said polarizedrelay. a Seeozid iriyed rel-Ja,

' le sf'laeeoataet lil i siid sonrie or altiens7 a Source Y neced to oneend or one eoridew' in circuit v.' il

ng current Yer ee relationslri *eliereo'fi :i r. 1eli-ed to other e.

par forisertion, a Contact eeuu -veted e nee rE :faid dire/et e irreritrelay, means for Connecting sind source. of

a re ra alternating current, said vibrating contact member and saiddirect current relay in series and contacts controlled by said directcurrent relay for opening or closing points in the signaling circuits.

11. A railway signaling system comprisingr in combination a pair oftrack rails, insulators dividing said rails into sections, impedancebonds bridging said insulators, a source of alternating current, atransformer having its primary fed from said source, a condenser, meansfor connecting tlie secondary of said transformer across said trackrails at one end of one of said sections in a circuit including saidcondenser, a polarized relay connected across said track rails at theother end of said section, a substantially aperiodic vibrating membercontrolled by said polarized relay, a second polarized relay, aresistance connected across the terminals of said second polarizedrelay, a second transformer having its primary also fed from saidsource, means for connecting the secondary of said second transi'ormer,said vibrating contact member and said second polarized relay in seriesand Contact members connected in the signaling' circuits and closed bysaid second polarized relay in its operated positions.

Signed by ine at Cheshire, England this 17th day of October 192x ALFREDERNEST HUDD.

